Although current research efforts have made strides in understanding the social, communication, and movement impairments that define autism, the neurologic basis of the disorder remains unclear. Given that autism is a developmental disorder, insight into its neurologic basis could be gained from careful investigation of processes important for acquiring (i.e., learning) specific skills. We hypothesize that deficits in procedural learning, particularly learning acquired through imitation, could help to explain the abnormal development of social, communicative and motor skills characteristic of autism. Abnormalities within cortical-subcortical circuits important for procedural learning have been observed in autism, particularly in the cerebellum and interconnected frontal and parietal areas;yet, to date, there has been little investigation of procedural skill-based learning in autism. The research proposed in the current application begins to address this, focusing on a careful and detailed assessment of motor skill learning in autism. Impaired motor skill learning could explain commonly observed difficulties in autism with acquiring patterns of movements necessary for performance of complex motor tasks. Development of social and communicative gestures (e.g., waving, blowing a kiss) also involves learning complex patterns of movements, many of which may be acquired through imitation, and learning of gestures through imitation may be important in developing a sense of "other minds" which is often impaired in autism. Preliminary findings from our laboratory reveal impaired motor learning in children with autism, particularly during tasks in which learning occurs in response to visual feedback;this would be consistent with reported deficits in visually-dependent motor imitation in autism. The goals of this proposal are to determine the common factors underlying motor learning deficits in autism, to examine the relationship of motor learning deficits to the social, communication, and movement impairments that characterize autism, and to investigate the neurologic contributions to these deficits using functional magnetic resonance imaging (fMRI). Knowledge about the nature of procedural learning deficits in children with autism could provide insights into the neurologic basis of the disorder as well as insights that are potentially useful to help guide behavioral, educational and other therapeutic interventions.